technic is
carefully carried out the bronchoscope will not be contaminated with
mouth secretions. The trachea is recognized as an open tube, with
whitish rings, and the expiratory blast can be felt and tubular
breathing heard; while if by mistake the bronchoscope has entered the
gullet it will be observed that the cervical esophagus has collapsed
walls. A puff of air may be felt and a fluttering sound heard when the
tube is in the esophagus, but these lack the intensity of the tracheal
blast. Usually a free flow of secretion is met with in the esophagus.
In diseased states the tracheal rings may not be visible because of
swollen mucosa, or the trachea itself may be in partial collapse from
external pressure. The true expiratory blast will, however, always be
recognized when the tube is in the trachea. Wide gagging of the mouth
renders exposure of the larynx difficult.

[FIG. 62.--Insertion of the bronchoscope. Note direction of the
trachea as indicated by the bronchoscope. Note that the patient's head
is held above the level of the table. The assistant's left hand should
be at the patient's mouth holding the bite-block. This is removed and
the assistant is on the wrong side of the table in the illustration in
order not to hide the position of the operator's hands. Note the
handle of the bronchoscope is to the right.]

[FIG. 63.--The heavy laryngoscope has been removed leaving the light
bronchoscope in position. The operator is inserting forceps. Note how
the left hand of the operator holds the tube lightly between the thumb
and first two fingers of the left hand, while the last two fingers are
hooked over the upper teeth of the patient "anchoring" the tube to
prevent it moving in or out or otherwise changing the relation of the
distal tube-mouth to a foreign body or a growth while forceps are
being used. Thus, also, any desired location of the tube can be
maintained in systematic exploration. The assistant's left hand is
dropped out of the way to show the operator's method. The assistant
during bronchoscopy holds the bite-block like a thimble on the index
finger of the left hand, and the assistant should be on the right side
of the patient. He is here put wrongly on the left side so as not to
hide the instruments and the manner of holding them.]

_Examination of the Trachea and Bronchi_.--All bronchial orifices must
be identified _seriatim_; because this is the only way by which the
bronchoscopist can know what part